Historically, missile flight direction control has been achieved by using thrust vector control (TVC), jet reaction control (JRC), canard control or tail fin control. However, each of these control methods has significant disadvantages. For example, even though TVC systems provide high controllability with minimal drag force, they are only effective during the boost portion of the flight. JRC systems can provide control during the entire flight and also have very low drag, but are limited by the amount of propellant that can be packaged in the missile. Canard and tail fin controls enable excellent controllability provided that the missile velocity is sufficient. The disadvantage is that canard and tail fin control systems can result in excessive drag.
Currently, there no known missiles that utilize deflection of the missile nosecone for controlling their flight paths.
The Magnetostrictive Missile Guidance System (MMGS) uses a movable nosecone that pivots about a single multi-directional joint on the missile axis in order to produce aerodynamic control forces for missile flight path control. The missile nosecone is driven by magnetostrictive materials in conjunction with a displacement amplification device. The determination of the nosecone deflection angle that is necessary to achieve any change in the flight path is made by a sensing device that produces position signals and a guidance computer that produces command signals for the desired flight path. The sensing device located in the nosecone senses the current position of the nosecone and this position signal is compared with the command signal by the computer to yield an error signal, which is indicative of the difference between the two input signals. Then appropriate magnetic field is applied to the magnetostrictive materials to cause them to grow in length and deflect the nosecone until the error signal is eliminated.
The significant control authority enabled by MMGS is available during both boost and coast, all without the disadvantage of excessive drag.